Shell structure impacts Camellia oleifera fruit splitting during dehydration

Abstract

This study aims to enhance the processing efficiency of Camellia oleifera fruit by exploring the potential relationship between the splitting characteristics during the dehydration process and the structure of the C. oleifera shell. The analysis focused on understanding the structural changes, moisture transfer, and shrinkage strain of the C. oleifera shell during the shelling processes. The results indicate that the essence of shelling C. oleifera fruit is the uneven shrinkage strain of the shell after dehydration, with the uneven shrinkage of the mesocarp being the primary driving force for the separation of seeds from the shell. Because the cuticle prevents moisture transfer and epidermal cells limit shell shrinkage, the exocarp can restrict the efficiency of the shell shrinkage strain. By damaging the exocarp structure, the shelling efficiency of C. oleifera fruit can be increased by more than 50 % under both natural drying and hot air drying. Moreover, under hot air drying, the shelling efficiency of C. oleifera fruit with a damaged exocarp at a low temperature (55 ℃) is 12.5 % higher than that of undamaged fruit at a high temperature (75 ℃). This study provides new insights into improving the shelling efficiency of C. oleifera fruit.